What is vapour pressure of liquids? How the vapour pressure of a liquid is related to its boiling point?

Explanation

The pressure exerted by vapour of a liquid when it is in equilibrium with liquid is known as vapour pressure.
Effect of temperature: When the temperature of a liquid increased the average kinetic energy of molecules increases. This increase in kinetic energy overcomes the attractive forces between the liquid molecules so that liquid molecules rapidly escape into air. Thus rise in temperature raises the escaping tendency of molecules. Hence the vapour pressure of a liquid increases with increase in temperature.
The vapour pressure of a liquid increases with increase of temperature. This goes on until the critical temperature of the liquid is reached. Above the critical temperature liquid state does not exist When the vapour pressure of the liquid becomes equal to the external (atmospheric) pressure the liquid is said to be boiling and the temperature at which this happens is known as bolling point.
for water the boiling point is `100^@ C ` at 1 atm pressure . if the external pressure is reduced the liquid boils at lower temperature . The boiling point of a liquid can be increased by increasing the external pressure .